Pregnancy Month by Month

The 40 weeks leading up to the birth of the baby is full of milestones and

physical transformations for both the mother and the growing baby.

This month by month visual guide provides an overview of the changes that occur to the growth of the fetus.

Trimester Month Weeks

One 1-4

First Two 5-8

Three 9-13

Four 14-17

Second Five 18-21

Six 22-26

Seven 27-30

Third Eight 31-35

Nine 36-40

Pregnancy Month by Month

1ST TRIMESTER 2ND TRIMESTER 3RD TRIMESTER

1 M

onth

2 M

onth

s

3 M

onth

s

4 M

onth

s

5 M

onth

s

6 M

onth

s

7 M

onth

s

8 M

onth

s

9 M

onth

s

Stages of Pregnancy

4 Weeks Pregnant

1 M

onth

2 M

onth

s

3 M

onth

s

4 M

onth

s

5 M

onth

s

6 M

onth

s

7 M

onth

s

8 M

onth

s

9 M

onth

s

EMBRYONIC STAGE

Placenta begins to develop.

Heart and digestive system begin to form.

Backbone and spinal cord start to form.

The baby is about the size of a poppy seed during week 4.

1.5mm 0.1g

in Lengthin Weight

8 Weeks Pregnant

1 M

onth

2 M

onth

s

3 M

onth

s

4 M

onth

s

5 M

onth

s

6 M

onth

s

7 M

onth

s

8 M

onth

s

9 M

onth

s

EMBRYONIC STAGE

Heart is functioning.

Eyes, nose and ears start to form.

Lips, tongue and teeth begin to form.

The baby is about the size of a raspberry during week 8.

13-16mm 1g

in Lengthin Weight

12 Weeks Pregnant

1 M

onth

2 M

onth

s

3 M

onth

s

4 M

onth

s

5 M

onth

s

6 M

onth

s

7 M

onth

s

8 M

onth

s

9 M

onth

s

FETAL STAGE

Baby develops recognisable form.

Arms, hands, fingers, legs, feet and toes are fully formed.

Baby has developed most organs and tissues.

The baby is about the size of a plum during week 12.

7.6cm 9-14g

in Lengthin Weight

16 Weeks Pregnant

1 M

onth

2 M

onth

s

3 M

onth

s

4 M

onth

s

5 M

onth

s

6 M

onth

s

7 M

onth

s

8 M

onth

s

9 M

onth

s

FETAL STAGE

Baby is developing reflexes such as sucking and swallowing.

Gender is identifiable.

Sweat glands are forming on palms and soles.

The baby is about the size of an avocado during week 16.

14.5cm 104g

in Lengthin Weight

20 Weeks Pregnant

1 M

onth

2 M

onth

s

3 M

onth

s

4 M

onth

s

5 M

onth

s

6 M

onth

s

7 M

onth

s

8 M

onth

s

9 M

onth

s

FETAL STAGE

Hair begins to grow on baby’s head.

Mother begins to feel fetal movement.

Eyebrows, eyelids and eyelashes appear.

The baby is about the size of a pomegranate during week 20.

24cm 303g

in Lengthin Weight

24 Weeks Pregnant

1 M

onth

2 M

onth

s

3 M

onth

s

4 M

onth

s

5 M

onth

s

6 M

onth

s

7 M

onth

s

8 M

onth

s

9 M

onth

s

FETAL STAGE

Eyelids begin to part and eyes can open briefly.

Skin is covered with a protective coating called vernix.

Baby is able to hiccup.

The baby is about the size of a coconut during week 24.

30cm 650g

in Lengthin Weight

28 Weeks Pregnant

1 M

onth

2 M

onth

s

3 M

onth

s

4 M

onth

s

5 M

onth

s

6 M

onth

s

7 M

onth

s

8 M

onth

s

9 M

onth

sFETAL STAGE

Taste buds have developed.

Fat layers are forming.

Organs are maturing.

The baby is about the size of an eggplant during week 28.

36cm 1100g

in Lengthin Weight

32 Weeks Pregnant

1 M

onth

2 M

onth

s

3 M

onth

s

4 M

onth

s

5 M

onth

s

6 M

onth

s

7 M

onth

s

8 M

onth

s

9 M

onth

s

FETAL STAGE

Tremendous brain growth occurs at this time.

Most body organs are developed except for the lungs.

The baby is about the size of a squash during week 32.

41cm 1800g

in Lengthin Weight

36 Weeks Pregnant

1 M

onth

2 M

onth

s

3 M

onth

s

4 M

onth

s

5 M

onth

s

6 M

onth

s

7 M

onth

s

8 M

onth

s

9 M

onth

sFETAL STAGE

The lungs are mature.

Skin is pink and smooth.

Baby starts to settle lower in the abdomen to prepare for birth.

The baby is about the size of a honeydew melon during week 36.

47.5cm 2600g

in Lengthin Weight

40 Weeks Pregnant

1 M

onth

2 M

onth

s

3 M

onth

s

4 M

onth

s

5 M

onth

s

6 M

onth

s

7 M

onth

s

8 M

onth

s

9 M

onth

s

FETAL STAGE

The baby is about the size of a pumpkin during week 40.

50cm 3400g

in Lengthin Weight

From early in pregnancy, babies can grow at different rates and therefore the numbers

provided in this guide are averages.

The information provided here should be used as a guide only and cannot substitute for

the advice of a medical professional.

Information provided in this guide was sourced from:healthnsw.gov.au | babies.sutterhealth.org

Genea Level 2, 321 Kent Street, Sydney, NSW 2000p 1300 361 795 e fertilityadvisor@genea.com.au